Apparatus and method for handling wafer carrier doors

ABSTRACT

An apparatus for handling wafer carriers in a semiconductor fabrication facility (FAB) is disclosed. In one example, the apparatus includes: a table configured to receive a wafer carrier having a first door and operable to hold a plurality of wafers; an opening mechanism configured to open the first door of the wafer carrier; and a door storage space configured to store the first door. The apparatus may be either located on a floor of the FAB or physically coupled to a ceiling of the FAB.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation application of U.S. patentapplication Ser. No. 16/834,290, filed Mar. 30, 2020, which is acontinuation application of U.S. patent application Ser. No. 15/883,473,filed Jan. 30, 2018, now U.S. Pat. No. 10,622,236, issued Apr. 14, 2020,which claims priority to U.S. Provisional Patent Application No.62/552,280, filed on Aug. 30, 2017, each of which is incorporated byreference herein in their entireties.

BACKGROUND

During manufacturing of a semiconductor device, the device is usuallyprocessed at many work stations or processing machines. The transportingor conveying of a partially finished device, or a work-in-process (WIP)part, is an important aspect in the total manufacturing process. Theconveying of semiconductor wafers is especially important in themanufacturing of integrated circuit (IC) chips due to the delicatenature of the chips. Furthermore, in fabricating an IC product, amultiplicity of fabrication steps, i.e. as many as several hundred, isusually required to complete the fabrication process. A semiconductorwafer or IC chips must be stored or transported between various processstations in order to perform various fabrication processes.

Automated Material Handling Systems (AMHS) have been widely used insemiconductor fabrication facilities (“FABs”) to automatically handleand transport groups or lots of wafers between various processingmachines (“tools”) used in chip manufacturing. Multiple wafers aretypically stored and transported together in wafer carriers by the AMHSbetween load ports of different wafer processing or other tools duringthe semiconductor fabrication process. The load port is used to handlenot only semiconductor wafers but also different types of substrates tobe processed such as liquid crystal display glass substrates andphotomask glass substrates.

The AMHS in a semiconductor FAB includes numerous types of automated andmanual vehicles for moving and transporting the wafer carriersthroughout the FAB during the manufacturing process. This can includefor example automatic guided vehicles (AGVs), personal guided vehicles(PGVs), rail guided vehicles (RGVs), overhead shuttles (OHSs), andoverhead hoist transports (OHTs). Of the foregoing AMHS wafer transportmechanisms, OHTs are commonly used to transport wafer carriers, from theload port of one tool to the load port of the next tool in theprocessing sequence. A wafer carrier transported by an OHT transfersystem typically has a door during the transfer process for productionquality control, e.g. to seal the wafer carrier against entry ofexternal contaminants to keep wafers inside the wafer carrier clean,and/or to protect the wafers from falling off the wafer carrier.

A conventional load port is used to load and unload a wafer carrier in aFAB. But it needs a human being to manually open the door of the wafercarrier and put the wafer carrier into the load port, which causes abottle neck of work efficiency in the FAB. As such, an apparatus andmethod for handling wafer carrier doors to solve the above mentionedproblems is desired.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that various features are not necessarily drawn to scale. In fact,the dimensions and geometries of the various features may be arbitrarilyincreased or reduced for clarity of discussion. Like reference numeralsdenote like features throughout specification and drawings.

FIG. 1 illustrates an exemplary load port with door opening, closing andstorage mechanisms, in accordance with some embodiments of the presentdisclosure.

FIG. 2A illustrates a front view of an exemplary door opening/closingmechanism in the load port shown in FIG. 1 , in accordance with someembodiments of the present disclosure.

FIG. 2B illustrates a corresponding back view of the exemplary dooropening/closing mechanism shown in FIG. 2A, in accordance with someembodiments of the present disclosure.

FIG. 3A illustrates a front view of an exemplary door storage space inthe load port shown in FIG. 1 , in accordance with some embodiments ofthe present disclosure.

FIG. 3B illustrates a corresponding back view of the exemplary doorstorage space shown in FIG. 3A, in accordance with some embodiments ofthe present disclosure.

FIG. 4A illustrates a front view of another exemplary load port withdoor opening, closing and storage mechanisms, in accordance with someembodiments of the present disclosure.

FIG. 4B illustrates a corresponding back view of the exemplary load portshown in FIG. 4A, in accordance with some embodiments of the presentdisclosure.

FIG. 5 illustrates an exemplary door opening/closing mechanism in theload port shown in FIG. 4A and FIG. 4B, in accordance with someembodiments of the present disclosure.

FIG. 6 illustrates an exemplary door storage space in the load portshown in FIG. 4A and FIG. 4B, in accordance with some embodiments of thepresent disclosure.

FIG. 7 illustrates a portion of a semiconductor FAB including a wafertransport tool and a load port, in accordance with some embodiments ofthe present disclosure.

FIG. 8 is a flow chart illustrating an exemplary method for handlingwafer carriers, in accordance with some embodiments of the presentdisclosure.

FIG. 9A is a flow chart illustrating another exemplary method forhandling wafer carriers, in accordance with some embodiments of thepresent disclosure.

FIG. 9B is a flow chart illustrating yet another exemplary method forhandling wafer carriers, in accordance with some embodiments of thepresent disclosure.

FIG. 10 illustrates a side view of an exemplary sky port with dooropening, closing and storage mechanisms, in accordance with someembodiments of the present disclosure.

FIG. 11 illustrates an exemplary sky port held on a ceiling of asemiconductor FAB, in accordance with some embodiments of the presentdisclosure.

FIG. 12A illustrates a portion of an exemplary Automated MaterialHandling System (AMHS), in accordance with some embodiments of thepresent disclosure.

FIG. 12B illustrates another portion of the exemplary AMHS shown in FIG.12A, in accordance with some embodiments of the present disclosure.

FIG. 13 illustrates a perspective view of an exemplary load port for aprocessing tool, in accordance with some embodiments of the presentdisclosure.

FIG. 14 illustrates a portion of a semiconductor FAB including atransport tool, a sky port and a load port, in accordance with someembodiments of the present disclosure.

FIG. 15 is a flow chart illustrating an exemplary method for handlingwafer carriers, in accordance with some embodiments of the presentdisclosure.

FIG. 16 is a flow chart illustrating another exemplary method forhandling wafer carriers, in accordance with some embodiments of thepresent disclosure.

DETAILED DESCRIPTION

The following disclosure describes various exemplary embodiments forimplementing different features of the subject matter. Specific examplesof components and arrangements are described below to simplify thepresent disclosure. These are, of course, merely examples and are notintended to be limiting. For example, the formation of a first featureover or on a second feature in the description that follows may includeembodiments in which the first and second features are formed in directcontact, and may also include embodiments in which additional featuresmay be formed between the first and second features, such that the firstand second features may not be in direct contact. In addition, thepresent disclosure may repeat reference numerals and/or letters in thevarious examples. This repetition is for the purpose of simplicity andclarity and does not in itself dictate a relationship between thevarious embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly. Terms such as“attached,” “affixed,” “connected” and “interconnected,” refer to arelationship wherein structures are secured or attached to one anothereither directly or indirectly through intervening structures, as well asboth movable or rigid attachments or relationships, unless expresslydescribed otherwise.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure belongs. It willbe further understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art and thepresent disclosure, and will not be interpreted in an idealized oroverly formal sense unless expressly so defined herein.

Reference will now be made in detail to the present embodiments of thedisclosure, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers are used in thedrawings and the description to refer to the same or like parts.

A typical FAB generally includes one or more floors having a pluralityof process bays including processing, metrology, and inspection toolsand wafer staging equipment such as stockers which are interconnected byan AMHS, which is computer controlled for handling the staging of wafersfor processing and flow of wafer traffic in the FAB. Multiple wafers aretypically stored and transported together in wafer carriers by the AMHSbetween load ports of different wafer processing or other tools duringthe semiconductor fabrication process. The wafer carriers includestandard mechanical interface (SMIF) pods which can hold a plurality ofwafers (e.g. 200 mm or 8 inch), or front opening unified pods (FOUPs)which can hold larger 300 mm (12 inch) or 450 mm (18 inch) wafers.Typically, each wafer carrier holds on the order of approximately 25wafers.

An OHT transfer system is commonly used to transport wafer carriers,such as FOUPs or SMIFs, from the load port of one tool to the load portof the next tool in the processing sequence. An OHT system includes“vehicles” that travel on an overhead monorail of the AMHS. The OHTvehicle on-board hoist is operable to raise and lower wafer carriersallowing the OHT vehicle to deposit and retrieve wafer carriers from theload ports of tools positioned along and on the floor beneath theoverhead rail. A wafer carrier transported by an OHT transfer systemtypically has a door during the transfer process for production qualitycontrol.

To improve production quality and save operation human resource, thepresent disclosure introduces an apparatus that can automatically openand close a door of a wafer carrier, and store the door in a doorstorage space when the wafer carrier is loaded for wafer processing.

In some embodiments, the apparatus is a load port located on a floor ofa FAB. The load port can hold the door opened from the wafer carrier andclose it back to the wafer carrier after wafer processing, withoutmoving the door to the door storage. In this case, the load port handleswafer carriers in series. In other embodiments, the load port moves thedoors opened from wafer carriers to the door storage, so that the loadport can handle wafer carriers in parallel and the opening mechanismdoes not need to hold the door and wait for the wafers to be processed.

In one embodiment, after a table of the load port receives a wafercarrier, e.g. from a transport tool like OHT, the load port has anopening mechanism to automatically open the door of the wafer carrierand move the door to a door storage unit for storing the door, while acontroller of the load port controls the table to load the opened wafercarrier for wafer processing. The load port may also have a closingmechanism to automatically retrieve a door from the storage and closethe door onto the wafer carrier after the wafer processing. Theretrieved door may not be the original door of the wafer carrier beforethe wafer carrier is loaded, but may have a same model as the originaldoor to fit the wafer carrier.

In some embodiments, the opening mechanism and the closing mechanism arecoupled together or combined together. The opening/closing mechanism andthe door storage space may be installed on an existing load port, e.g. amulti-cassette load port (MCLP), that is located on a floor of a FAB.The opening/closing mechanism may include: a vacuum pin to hold thedoor, a latch key to open/close the door, and a moving mechanism to movethe door to or from the door storage. The door storage may include oneor more storage units each for storing a wafer carrier door. The movingmechanism can fix the door to a door storage unit, e.g. by an alignmentpin.

In some embodiments, the door storage units are covered by a transparentplate, such that an operator standing in front of the load port can seethe doors stored in the storage units that are located behind and abovethe table. The load port may include a plurality of buffering spaces tobuffer the wafer carriers before any wafer in the buffered wafercarriers is processed. From the operator's point of view, the pluralityof buffering spaces may be located at the back side of the wafercarrier, at the left side of the wafer carrier, or at the right side ofthe wafer carrier, according to various embodiments. Corresponding, thetable may be configured to move the wafer carrier into a bufferingspace, from front to back, from left to right, or from right to left,according to various embodiments.

The apparatus may also include a light shutter to capture lightinformation of a wafer transport path between the light shutter and thetable, and a sensor, e.g. an E84 sensor, to detect an obstacle on thewafer transport path based on the light information and inform the OHTabout the detected obstacle, and thereafter stop the OHT fromtransferring wafer carriers onto the table.

In some embodiment, the apparatus has one or more holding mechanismsconfigured to hold the apparatus to a ceiling of a FAB. In this case,the apparatus is called a “sky port” and may be separate from a loadport that loads the wafer carrier for wafer processing. The sky port canautomatically open and close a door of a wafer carrier, and store thedoor in a door storage space when the wafer carrier is loaded by theload port. In one example, a bottom portion of the sky port is higherthan a top portion of the load port. In another example, the sky port islocated right above the load port.

The present disclosure is applicable to all kinds of devices that dealwith a wafer carrier having a door. The disclosed apparatus canautomatically map each wafer carrier to a door; and automaticallycontrol the process flow including door opening, storing, and closing,to save human operation resources and reduce human errors on themanufacturing floor. In one example, the apparatus can save floor areaof a FAB by being installed on a ceiling of the FAB.

FIG. 1 illustrates an exemplary load port 110 with door opening, closingand storage mechanisms, in accordance with some embodiments of thepresent disclosure. As shown in FIG. 1 , the load port 110 includes ahousing 111, a table 112, a light shutter 114, a door opening/closingmechanism 116, and a door storage space 118. The load port 110 may belocated on a floor of a FAB for handling wafer carriers.

The table 112 may be configured to receive a wafer carrier 120 from atransport tool, e.g. a vehicle of an OHT that is physically coupled to aceiling of the FAB and is located higher than the table 112. The wafercarrier 120 has a door 122 on the back of the wafer carrier 120, i.e. onthe side facing the housing 111.

The door opening/closing mechanism 116 in this example is coupled to thehousing 111 and located at the front side of the housing 111, i.e. atthe side facing the wafer carrier 120. The door opening/closingmechanism 116 may be configured to open the door 122 of the wafercarrier 120, e.g. by a latch key and vacuum pin, and move the door 122away from the wafer carrier 120 toward the back of the wafer carrier 120along the −X direction as shown in FIG. 1 . The door opening/closingmechanism 116 may then hold the door 122 and move it up along the Zdirection to the door storage 118.

The door storage 118 in this example is coupled to the housing 111 andlocated at the front side of the housing 111, i.e. at the side facingthe wafer carrier 120. The door storage 118 may be physically connectedto the door opening/closing mechanism 116. The door opening/closingmechanism 116 is movable relative to the door storage space 118, alongthe Z and −Z directions. The door storage 118 in this example includesfour door storage units. It can be understood that a door storage spacemay include one or more door storage units for storing wafer carrierdoors. For example, after moving the door 122 up to one of the doorstorage units, the door opening/closing mechanism 116 may rotate doorpin by the latch key to fix the door 122 into the door storage unit. Thedoor 122 is stored in the door storage unit while the wafer carrier 120is loaded for wafer processing.

The light shutter 114 in this example is coupled to the housing 111 andlocated at the front side of the housing 111 and above the table 112.The wafer carrier 120 is transported by a transport tool, e.g. an OHT,from up of the load port 110 along the −Z direction, through the lightshutter 114 and down to the table 112. The light shutter 114 can capturelight information of a wafer transport path between the light shutter114 and the table 112. Because any wafer carrier is received by thetable 112 through the wafer transport path, if there is any object orobstacle located on the wafer transport path, continuing transportingwafer carriers may cause a collision. As such, a sensor (not shown),e.g. an E84 sensor, that is electrically connected to the light shutter114 may determine whether there is an obstacle on the wafer transportpath based on the light information captured by the light shutter 114and send a signal to the OHT, to stop OHT from transporting any morewafer carrier onto the table 112, until the wafer transport path isclear and has no obstacle. For example, after an E84 sensor connected tothe light shutter 114 determines that there is an obstacle between thelight shutter 114 and the table 112, the E84 sensor may inform anothersensor, e.g. an E87 sensor, connected to the OHT, about the obstacle tostop OHT from transporting wafer carriers to the table 112. Then, afterthe light information reflects that obstacle is gone and the wafertransport path is clear, the E84 sensor may inform the E87 sensor withanother signal, to ask the OHT to continue transporting wafer carriersto the table 112.

The housing 111 has an input gateway 119 facing the back side of thewafer carrier 120. The table 112 is movable relative to the housing 111.In one embodiment, the load port 110 also includes a controller 113. Thecontroller 113 may control the table 112 to move the wafer carrier 120through the input gateway 119 and into a buffering space along the −Xdirection, i.e. to load the wafer carrier 120 into the buffering spacefor a processing tool to process at least one wafer in the wafer carrier120.

A processing tool (not shown in FIG. 1 ) may be coupled to the load port110 for retrieving and processing at least one wafer in the wafercarrier 120 whose door has been opened and stored in the door storagespace 118. The processing tool may be a manufacturing apparatus, avisual inspection apparatus, an electrical characteristic testapparatus, etc.

In accordance with various embodiments, the controller 113 may bedisposed under the table 112 as shown in FIG. 1 , or disposed within thehousing 111, or disposed at other places of the load port 110. Thecontroller 113 may be electrically or mechanically connected to thetable 112 for controlling the table 112. After the processing toolfinishes processing the at least one wafer in the wafer carrier 120, thecontroller 113 may control the table 112 to unload the wafer carrier 120from the buffering space.

After the wafer carrier 120 is unloaded, the door opening/closingmechanism 116 may be configured to retrieve a door from the door storagespace 118. The retrieved door may be the original door 122 of the wafercarrier 120 before the wafer carrier 120 is loaded, or may be anotherdoor having a same model as the original door 122 to fit the wafercarrier 120. The door opening/closing mechanism 116 may hold and movedown the retrieved door along the −Z direction from the correspondingstorage unit and close the retrieved door onto the wafer carrier 120,e.g. by a latch key and vacuum pin. The OHT may then transport theunloaded wafer carrier 120 to another load port for further processingof the one or more wafers in the wafer carrier 120.

In addition to a simple load port supporting one cassette or one wafercarrier at a time, as described above, the present teaching is alsoapplicable to a multi-cassette load port (MCLP). When the load port 110is a MCLP, multiple buffering spaces (not shown in FIG. 1 ) are movablydisposed in the housing 111. For wafer carrier loading, the controller113 may first control the plurality of buffering spaces to move up ordown along the Z or −Z direction, such that one of the buffering spacesis aligned with the table 112. The controller 113 may then control thetable 112 to move the wafer carrier 120 through the input gateway 119and into an aligned buffering space along the −X direction, i.e. to loadthe wafer carrier 120 into the aligned buffering space for a processingtool to process at least one wafer in the wafer carrier 120. Theprocessing tool (not shown in FIG. 1 ) may be coupled to the load port110 for retrieving and processing wafers in the wafer carriers (whosedoors have been opened and stored in the door storage space 118) thatare buffered in the plurality of buffering spaces in the housing 111.The processing tool may be a manufacturing apparatus, a visualinspection apparatus, an electrical characteristic test apparatus, etc.

For wafer carrier unloading of the MCLP, after the processing toolfinishes processing the at least one wafer in the wafer carrier 120, thecontroller 113 may control the table 112 to unload the wafer carrier 120from the aligned buffering space. It can be understood that since thereare multiple wafer carriers buffered in the buffering spaces of the MCLPwaiting for wafer processing, the previously aligned buffering space maybe misaligned with the table 112. In this case, the controller 113 mayfirst control the buffering spaces to move up or down along the Z or −Zdirection to realign the previously aligned buffering space with thetable 112, before controlling the table 112 to unload the wafer carrier120 from the realigned buffering space.

The operations of the light shutter 114, the door opening/closingmechanism 116 and the door storage space 118 in the MCLP may be same orsimilar to what have been described for the simple load port describedabove.

In accordance with the embodiment shown in FIG. 1 , the housing 111including the plurality of buffering spaces is located at the back sideof the wafer carrier 120, from an operator's point of view when theoperator is standing in front of the load port 110 and facing the doorstorage space 118. In this case, the table 112 is configured to move thewafer carrier 120 into a buffering space from front to back, from theoperator's point of view.

FIG. 2A illustrates a front view of an exemplary door opening/closingmechanism 116 in the load port shown in FIG. 1 , in accordance with someembodiments of the present disclosure. FIG. 2B illustrates acorresponding back view of the exemplary door opening/closing mechanism116 shown in FIG. 2A, in accordance with some embodiments of the presentdisclosure.

As shown in FIG. 2A and FIG. 2B, the door opening/closing mechanism 116in this example includes a key plate 230 holding a pair of latch keys210-1, 210-2 and a pair of vacuum pins 220-1, 220-2, and a pair of rails240-1, 240-2 supporting movement of the key plate 230, with or without awafer carrier door, along the Z and −Z directions. The pair of latchkeys 210-1, 210-2 and the pair of vacuum pins 220-1, 220-2 are coupledon the front side of the key plate 230, i.e. facing the door 122 of thewafer carrier 120 along the X direction before the door 122 is opened.As shown in FIG. 2B, the door 122 in this example includes a pair oflatch key grooves 124 (only one of them is shown in FIG. 2B) and a pairof suction holes 126 (only one of them is shown in FIG. 2B), attached onthe door's side facing the key plate 230.

The door opening/closing mechanism 116 may also include a motor (or anengine, not shown in FIG. 2A and FIG. 2B) configured to providemechanical energy for the key plate 230 to move up or down on the pairof rails 240-1, 240-2 along the Z or −Z direction, and move front orback using a jack (not shown in FIG. 2A and FIG. 2B) along the X or −Xdirection.

To open the door 122, the key plate 230 can move down along the −Zdirection to be aligned with the door 122, then move toward the door 122along the X direction such that the pair of latch keys 210-1, 210-2 areinserted into the pair of latch key grooves 124, and the pair of vacuumpins 220-1, 220-2 are inserted into the pair of suction holes 126. Eachvacuum pin may include a vacuum hole through which a vacuum pressure isapplied, when the vacuum pin is inserted into a corresponding suctionhole on the door 122. Based on the vacuum pressure, the door 122 issucked to and held by the key plate 230, such that the key plate 230 canmove with the door 122 after the door 122 is unlocked or opened. Beforeor after the door 122 is pulled against the key plate 230, the pair oflatch keys 210-1, 210-2 can be used to rotate the lock on the door 122,e.g. by 90°, to unlock the door 122. After the door 122 is unlocked fromthe wafer carrier 120 and is held or pulled against the key plate 230,the key plate 230 may move the door 122 away from the wafer carrier 120along the −X direction, and then move the door 122 up to a correspondingdoor storage unit along the Z direction for door storage.

To close a door onto the wafer carrier 120, the key plate 230 may moveto a door storage unit that stores the door 122 or stores a door havinga same model as the door 122, and retrieve the door from the doorstorage unit. Then the key plate 230 can move down with the retrieveddoor along the −Z direction to be aligned with the wafer carrier 120,then move toward the wafer carrier 120 along the X direction such thatthe retrieved door is put onto the wafer carrier 120. The pair of latchkeys 210-1, 210-2 can be used to rotate the lock on the retrieved door,e.g. by 90°, to lock the retrieved door onto the wafer carrier 120. Thenthe vacuum pressure is released through the vacuum pins, such that theretrieved door is separable from the key plate 230. After the retrieveddoor is locked onto the wafer carrier 120 and is separable from the keyplate 230, the key plate 230 may move back away from the wafer carrier120 along the −X direction.

In some embodiments, the door opening mechanism and the door closingmechanism may be one mechanism, i.e. the door opening/closing mechanism116 as shown in FIG. 2A and FIG. 2B. In other embodiments, the dooropening mechanism may be a separate mechanism from the door closingmechanism.

FIG. 3A illustrates a front view of an exemplary door storage space 118in the load port shown in FIG. 1 , in accordance with some embodimentsof the present disclosure. FIG. 3B illustrates a corresponding back viewof the exemplary door storage space 118 shown in FIG. 3A, in accordancewith some embodiments of the present disclosure.

As shown in FIG. 3A and FIG. 3B, the door storage space 118 in thisexample includes a plurality of door storage units 310, disposed alongthe Z direction. It can be understood that according to variousembodiments, one or more door storage units may be included in the doorstorage space 118. Each door storage unit can store a wafer carrier door322 while the wafer carrier is loaded for wafer processing.

As discussed above, after the door 122 is unlocked from the wafercarrier 120 and is held or pulled against the key plate 230, the keyplate 230 may move the door 122 away from the wafer carrier 120 alongthe −X direction, and then move the door 122 up on the pair of rails240-1, 240-2 along the Z direction to a corresponding door storage unit,that is not attached with any door, for door storage. To store the door122, after the key plate 230 moves the door 122 to be aligned with thecorresponding door storage unit, the door 122 may be fixed or attachedto the corresponding door storage unit based on a door storagemechanism. In one example, the pair of latch keys 210-1, 210-2 may beused to rotate the lock on the door 122, e.g. by 90°, to lock the door122 onto a corresponding plate 312 at the corresponding door storageunit. In another example, the door 122 may be fixed at the correspondingdoor storage unit by a separate alignment pin 320. The plate 312 may bea separate plate for each door storage unit as shown in FIG. 3A, or maybe a one-piece plate covering the entire door storage space 118. In someembodiments, the plate may be transparent such that a person can see howmany wafer carrier doors 322 have been stored in the door storage space118.

Similarly, to retrieve a door from a door storage unit, the key plate230 may move to be aligned with the corresponding door storage unit, andunlock the door from the door storage unit, based on the door storagemechanism. In one example, the pair of latch keys 210-1, 210-2 may beused to rotate the lock on the retrieved door, e.g. by 90°, to unlockthe retrieved door from a corresponding plate 312 at the correspondingdoor storage unit. In another example, the retrieved door may bedetached from the corresponding door storage unit by releasing theseparate alignment pin 320. The retrieved door may be the door 122 or adoor having a same model as the door 122. After the retrieved door isunlocked from the corresponding door storage unit and is held or pulledagainst the key plate 230, the key plate 230 may move the retrieved doordown on the pair of rails 240-1, 240-2 along the −Z direction to alignthe retrieved door with the wafer carrier, for door closing as describedabove.

In some embodiments, the door storage mechanism may be connected to thedoor opening/closing mechanism 116 as shown in FIG. 3A and FIG. 3B. Inother embodiments, the door storage mechanism may be separate from thedoor opening/closing mechanism 116.

FIG. 4A illustrates a front view of another exemplary load port 410 withdoor opening, closing and storage mechanisms, in accordance with someembodiments of the present disclosure. FIG. 4B illustrates acorresponding back view of the exemplary load port 410 shown in FIG. 4A,in accordance with some embodiments of the present disclosure.

As shown in FIG. 4A and FIG. 4B, the load port 410 includes a housing411, a table 412, a light shutter 414, a door opening/closing mechanism416, and a door storage space 418. The load port 410 may be located on afloor of a FAB for handling wafer carriers.

The table 412 may be configured to receive a wafer carrier 420 from atransport tool, e.g. a vehicle of an OHT that is physically coupled to aceiling of the FAB and is located higher than the table 412. The wafercarrier 420 has a door (not shown in FIG. 4A and FIG. 4B) on the back ofthe wafer carrier 420, i.e. on the side facing the door storage space418.

The door opening/closing mechanism 416 in this example is coupled to thehousing 411 and located at the left side of the housing 411, i.e. on theside toward the X′ direction compared to the housing 411, as shown inFIG. 4A and FIG. 4B. The door opening/closing mechanism 416 may beconfigured to open the door of the wafer carrier 420, e.g. by a latchkey and vacuum pin, and move the door away from the wafer carrier 420toward the back of the wafer carrier 420 along the −Y′ direction asshown in FIG. 4A and FIG. 4B. The door opening/closing mechanism 416 maythen hold the door and move it up along the Z′ direction to the doorstorage space 418.

The door storage space 418 in this example is coupled to the housing 411and located at the left side of the housing 411, i.e. on the side towardthe X′ direction compared to the housing 411. The door storage 418 maybe physically connected to the door opening/closing mechanism 416. Thedoor opening/closing mechanism 416 is movable relative to the doorstorage space 418, along the Z′ and −Z′ directions. The door storagespace 418 in this example includes four door storage units. It can beunderstood that a door storage space may include one or more doorstorage units for storing wafer carrier doors. For example, after movingthe door up to one of the door storage units, the door opening/closingmechanism 416 may rotate door pin by the latch key to fix the door intothe door storage unit. The door is stored in the door storage unit whilethe wafer carrier 420 is loaded for wafer processing.

The light shutter 414 in this example is coupled to the housing 411 andlocated at the left side of the housing 411 and above the table 412. Thewafer carrier 420 is transported by a transport tool, e.g. an OHT, fromup of the load port 410 along the −Z direction, through the lightshutter 414 and down to the table 412. The light shutter 414 can capturelight information of a wafer transport path between the light shutter414 and the table 412. Because any wafer carrier is received by thetable 412 through the wafer transport path, if there is any object orobstacle located on the wafer transport path, continuing transportingwafer carriers may cause a collision. As such, a sensor (not shown),e.g. an E84 sensor, that is electrically connected to the light shutter414 may determine whether there is an obstacle on the wafer transportpath based on the light information captured by the light shutter 414and send a signal to the OHT, to stop OHT from transporting any morewafer carrier onto the table 412, until the wafer transport path isclear and has no obstacle. For example, after an E84 sensor connected tothe light shutter 414 determines that there is an obstacle between thelight shutter 414 and the table 412, the E84 sensor may inform anothersensor, e.g. an E87 sensor, connected to the OHT, about the obstacle tostop OHT from transporting wafer carriers to the table 412. Then, afterthe light information reflects that obstacle is gone and the wafertransport path is clear, the E84 sensor may inform the E87 sensor withanother signal, to ask the OHT to continue transporting wafer carriersto the table 412.

The housing 411 in this example has an input gateway 419 facing theright side of the wafer carrier 420. The table 412 is movable relativeto the housing 411. In one embodiment, the load port 410 also includes acontroller 413. The controller 413 may control the table 412 to move thewafer carrier 420 through the input gateway 419 and into a bufferingspace along the −X′ direction, i.e. to load the wafer carrier 420 intothe buffering space for a processing tool to process at least one waferin the wafer carrier 420.

A processing tool (not shown in FIG. 4A or FIG. 4B) may be coupled tothe load port 410 for retrieving and processing at least one wafer inthe wafer carrier 420 whose door has been opened and stored in the doorstorage space 418. The processing tool may be a manufacturing apparatus,a visual inspection apparatus, an electrical characteristic testapparatus, etc.

In accordance with various embodiments, the controller 413 may bedisposed under the table 412 as shown in FIG. 4A and FIG. 4B, ordisposed within the housing 411, or disposed at other places of the loadport 410. The controller 413 may be electrically or mechanicallyconnected to the table 412 for controlling the table 412. After theprocessing tool finishes processing the at least one wafer in the wafercarrier 420, the controller 413 may control the table 412 to unload thewafer carrier 420 from the buffering space.

After the wafer carrier 420 is unloaded, the door opening/closingmechanism 416 may be configured to retrieve a door from the door storagespace 418. The retrieved door may be the original door of the wafercarrier 420 before the wafer carrier 420 is loaded, or may be anotherdoor having a same model as the original door to fit the wafer carrier420. The door opening/closing mechanism 416 may hold and move down theretrieved door along the −Z′ direction from the corresponding storageunit and close the retrieved door onto the wafer carrier 420, e.g. by alatch key and vacuum pin. The OHT may then transport the unloaded wafercarrier 420 to another load port for further processing of the one ormore wafers in the wafer carrier 420.

In addition to a simple load port supporting one cassette or one wafercarrier at a time, as described above, the present teaching is alsoapplicable to a multi-cassette load port (MCLP). When the load port 410is a MCLP, there is a plurality of buffering spaces 417 movably disposedin the housing 411. For wafer carrier loading, the controller 413 mayfirst control the plurality of buffering spaces 417 to move up or downalong the Z′ or −Z′ direction, such that one of the buffering spaces 417is aligned with the table 412. The controller 413 may then control thetable 412 to move the wafer carrier 420 through the input gateway 419and into an aligned buffering space along the −X′ direction, i.e. toload the wafer carrier 420 into the aligned buffering space for aprocessing tool to process at least one wafer in the wafer carrier 420.The processing tool (not shown in FIG. 4A or FIG. 4B) may be coupled tothe load port 410 for retrieving and processing wafers in the wafercarriers (whose doors have been opened and stored in the door storagespace 418) that are buffered in the plurality of buffering spaces 417 inthe housing 411.

For wafer carrier unloading of the MCLP, after the processing toolfinishes processing the at least one wafer in the wafer carrier 420, thecontroller 413 may control the table 412 to unload the wafer carrier 420from the aligned buffering space. It can be understood that since thereare multiple wafer carriers buffered in the buffering spaces 417 of theMCLP waiting for wafer processing, the previously aligned bufferingspace may be misaligned with 412. In this case, the controller 413 mayfirst control the buffering spaces to move up or down along the Z′ or−Z′ direction to realign the previously aligned buffering space with thetable 412, before controlling the table 412 to unload the wafer carrier420 from the realigned buffering space.

The operations of the light shutter 414, the door opening/closingmechanism 416 and the door storage space 418 in the MCLP may be same orsimilar to what have been described for the simple load port describedabove.

In accordance with the embodiment shown in FIG. 4A and FIG. 4B, thehousing 411 including the plurality of buffering spaces 417 is locatedat the right side of the wafer carrier 420, from an operator's point ofview when the operator is standing in front of the load port 410 andfacing the door storage space 418. In this case, the table 412 isconfigured to move the wafer carrier 420 into a buffering space fromleft to right, from the operator's point of view.

It can be understood that in some other embodiments, the housing of theload port including buffering spaces may be located at the left side ofthe wafer carrier, and the table is configured to move the wafer carrierinto a buffering space from right to left, from the operator's point ofview.

As shown in FIG. 4A and FIG. 4B, the load port 410 further includes aplurality of key-switches 415. Different components of the load port410, e.g. the controller 413, the door opening/closing mechanism 416,the door storage space 418, etc., may be configured to operate based ona pressed signal generated by any of the key-switches 415.

FIG. 5 illustrates an exemplary door opening/closing mechanism 416 inthe load port 410 shown in FIG. 4A and FIG. 4B, in accordance with someembodiments of the present disclosure. As shown in FIG. 5 , the dooropening/closing mechanism 416 in this example includes a key plate 530holding a pair of latch keys 510-1, 510-2 and a pair of vacuum pins520-1, 520-2, and a pair of rails 540-1, 540-2 supporting movement ofthe key plate 530, with or without a wafer carrier door, along the Z′and −Z′ directions. The pair of latch keys 510-1, 510-2 and the pair ofvacuum pins 520-1, 520-2 are coupled on the front side of the key plate530, i.e. facing the door of the wafer carrier 420 along the Y′direction before the door is opened. The door in this example mayinclude a pair of latch key grooves (not shown in FIG. 5 ) and a pair ofsuction holes (not shown in FIG. 5 ), attached on the door's side facingthe key plate 530.

The door opening/closing mechanism 416 may also include a motor (or anengine) 560 configured to provide mechanical energy for the key plate530 to move up or down on the pair of rails 540-1, 540-2 along the Z′ or−Z′ direction, and move front or back using a jack 550 along the Y′ or−Y′ direction.

To open the wafer carrier door, the key plate 530 can move down alongthe −Z′ direction to be aligned with the door, then move toward the dooralong the Y′ direction such that the pair of latch keys 510-1, 510-2 areinserted into the pair of latch key grooves, and the pair of vacuum pins520-1, 520-2 are inserted into the pair of suction holes. Each vacuumpin may include a vacuum hole through which a vacuum pressure isapplied, when the vacuum pin is inserted into a corresponding suctionhole on the door. Based on the vacuum pressure, the door is sucked toand held by the key plate 530, such that the key plate 530 can move withthe door after the door is unlocked or opened. Before or after the dooris pulled against the key plate 530, the pair of latch keys 510-1, 510-2can be used to rotate the lock on the door, e.g. by 90°, to unlock thedoor. After the door is unlocked from the wafer carrier 420 and is heldor pulled against the key plate 530, the key plate 530 may move the dooraway from the wafer carrier 420 along the −Y′ direction, and then movethe door up to a corresponding door storage unit along the Z′ directionfor door storage.

To close a door onto the wafer carrier 420, the key plate 530 may moveto a door storage unit that stores the door or stores a door having asame model as the door, and retrieve the door from the door storageunit. Then the key plate 530 can move down with the retrieved door alongthe −Z′ direction to be aligned with the wafer carrier 420, then movetoward the wafer carrier 420 along the Y′ direction such that theretrieved door is put onto the wafer carrier 420. The pair of latch keys510-1, 510-2 can be used to rotate the lock on the retrieved door, e.g.by 90°, to lock the retrieved door onto the wafer carrier 420. Then thevacuum pressure is released through the vacuum pins, such that theretrieved door is separable from the key plate 530. After the retrieveddoor is locked onto the wafer carrier 420 and is separable from the keyplate 530, the key plate 530 may move back away from the wafer carrier420 along the −Y′ direction.

In some embodiments, the door opening mechanism and the door closingmechanism may be one mechanism, i.e. the door opening/closing mechanism416 as shown in FIG. 5 . In other embodiments, the door openingmechanism may be a separate mechanism from the door closing mechanism.

FIG. 6 illustrates an exemplary door storage space 418 in the load port410 shown in FIG. 4A and FIG. 4B, in accordance with some embodiments ofthe present disclosure. As shown in FIG. 6 , the door storage space 418in this example includes a plurality of door storage units 610, disposedalong the Z′ direction. It can be understood that according to variousembodiments, one or more door storage units may be included in the doorstorage space 418. Each door storage unit can store a wafer carrier doorwhile the wafer carrier is loaded for wafer processing.

As discussed above, after the door is unlocked from the wafer carrier420 and is held or pulled against the key plate 530, the key plate 530may move the door away from the wafer carrier 420 along the −Y′direction, and then move the door up on the pair of rails 540-1, 540-2along the Z′ direction to a corresponding door storage unit, that is notattached with any door, for door storage. To store the door, after thekey plate 530 moves the door to be aligned with the corresponding doorstorage unit, the door may be fixed or attached to the correspondingdoor storage unit based on a door storage mechanism. In one example, thepair of latch keys 510-1, 510-2 may be used to rotate the lock on thedoor, e.g. by 90°, to lock the door onto a corresponding plate 612 atthe corresponding door storage unit. In another example, the door may befixed at the corresponding door storage unit by a separate alignment pin(not shown in FIG. 6 ). The plate 612 may be a one-piece plate coveringthe entire door storage space 418 as shown in FIG. 6 or may be aseparate plate for each door storage unit. As shown in FIG. 6 , theplate 612 may be transparent such that a person can see how many wafercarrier doors have been stored in the door storage space 418.

Similarly, to retrieve a door from a door storage unit, the key plate530 may move to be aligned with the corresponding door storage unit, andunlock the door from the door storage unit, based on the door storagemechanism. In one example, the pair of latch keys 510-1, 510-2 may beused to rotate the lock on the retrieved door, e.g. by 90°, to unlockthe retrieved door from a corresponding plate 612 at the correspondingdoor storage unit. In another example, the retrieved door may bedetached from the corresponding door storage unit by releasing theseparate alignment pin. The retrieved door may be the original door or adoor having a same model as the original door. After the retrieved dooris unlocked from the corresponding door storage unit and is held orpulled against the key plate 530, the key plate 530 may move theretrieved door down on the pair of rails 540-1, 540-2 along the −Z′direction to align the retrieved door with the wafer carrier, for doorclosing as described above.

In some embodiments, the door storage mechanism may be a same mechanismas the door opening/closing mechanism 416 as shown in FIG. 6 . In otherembodiments, the door storage mechanism may be a different mechanismfrom the door opening/closing mechanism 416.

FIG. 7 illustrates a portion of a semiconductor FAB 700 including awafer transport tool 740 and a load port 710, in accordance with someembodiments of the present disclosure. The portion of the FAB 700 shownin FIG. 7 may be a schematic perspective diagram of an automaticmaterial handling system (AMHS). As shown in FIG. 7 , the AMHS includesa wafer transport tool 740, e.g. an OHT system, and a load port 710,which may be any load port as disclosed above in accordance with FIGS.1-6 , e.g. an MCLP.

In one example, the OHT system 740 includes a network of stationarytracks or rails 742 operable to guide the movement of one or morewheeled OHT vehicles 750 supported and suspended from the rails 742. Insome embodiments, the rails 742 are monorails that are mounted to andsuspended from the ceiling 780 and/or walls of the FAB. Rails 742 haveany suitable cross-sectional configuration as will be appreciated bythose in the art so long as the OHT vehicle 750 are appropriatelysupported from the rail 742 for rolling motion.

An OHT vehicle 750 is operable to transport a wafer carrier 720 throughthe FAB 700 for intra-bay or inter-bay movement. The OHT vehicle 750 isconfigured and structured to hold a wafer carrier 720 housing aplurality of wafers and transport the wafer carrier 720 in a generallyhorizontal or lateral direction from one location to another within theFAB 700.

The OHT vehicle 750 is configured and operable to pick up, raise/lower,hold, articulate, and release a wafer carrier 720. In one embodiment,the OHT vehicle 750 includes a motor-driven or pneumatic hoistingmechanism 752 generally comprised of gripper assembly including one ormore retractable and extendable gripper arms having a gripper on the endthereof configured for locking onto a mating hook or flange on the wafercarrier 720. The hoisting mechanism 752 is operable to vertically raiseand lower the gripper and attached wafer carrier 720.

As shown in FIG. 7 , the OHT vehicle 750 can hold the wafer carrier 720,transport the wafer carrier 720 along the rail 742, and release thewafer carrier 720 onto the table of the load port 710. The load port 710can automatically open and store the door of the wafer carrier 720 andload the wafer carrier 720 for a processing tool 730 to process at leastone wafer in the wafer carrier 720, in a manner similar to what havebeen described in FIGS. 1-6 . In this example, the processing tool 730is coupled to the load port 710. Both the load port 710 and theprocessing tool 730 are located on the floor 790 of the FAB 700.

In some embodiments, there are multiple processing tools in the FAB 700,and each processing tool is coupled to a corresponding load port that isa load port as disclosed above in accordance with FIGS. 1-6 . In thissituation, after the at least one wafer in the wafer carrier 720 isprocessed and the wafer carrier 720 is unloaded by the load port 710,the OHT vehicle 750 can pick up the wafer carrier 720 from the load port710 and transport the wafer carrier 720 to a next load port foradditional wafer processing at the processing tool coupled to the nextload port.

FIG. 8 is a flow chart illustrating an exemplary method 800 for handlingwafer carriers, in accordance with some embodiments of the presentdisclosure. As shown in FIG. 8 , a wafer carrier having a door andoperable to hold a plurality of wafers, is received at 802. The door ofthe wafer carrier is opened at 804. The door is stored at 806 in astorage space of a device located on a floor of a FAB. As discussedabove, the device may be a load port, e.g. an MCLP, coupled to aprocessing tool. At 808, the wafer carrier is loaded by the device forthe processing tool to process at least one wafer in the wafer carrier.

FIG. 9A is a flow chart illustrating another exemplary method 900 forhandling wafer carriers, in accordance with some embodiments of thepresent disclosure. As shown in FIG. 9A, a wafer carrier having a firstdoor and operable to hold a plurality of wafers, is received at 902. Thefirst door of the wafer carrier is opened with a latch key at 904. Thefirst door is moved away at 906 from the wafer carrier along a firstdirection. The first door is moved at 908 along a direction differentfrom the first direction to a storage unit. The first door is attachedat 910 onto the storage unit in a device for storing the first door. Asdiscussed above, the device may be a load port, e.g. an MCLP, located ona floor of a FAB.

At 912, the wafer carrier is moved along the first direction into abuffering space. The wafer carrier is loaded at 914 for processing atleast one wafer in the wafer carrier. After being loaded, the wafercarrier is unloaded at 916. A second door having a same model as thefirst door is retrieved at 918. The second door is closed at 920 ontothe wafer carrier.

FIG. 9B is a flow chart illustrating yet another exemplary method 901for handling wafer carriers, in accordance with some embodiments of thepresent disclosure. The exemplary method 901 is similar to the exemplarymethod 900, except that the step 912 is replaced by the step 913, wherethe wafer carrier is moved along a direction orthogonal to the firstdirection into a buffering space. As discussed above, an operator maystand on the front side of a wafer carrier on the table of the load portas disclosed herein, while the door of the wafer carrier is located onthe back side of the wafer carrier, although the disclosed load port canautomatically operate the wafer carrier without a human operator. Inthis scenario, from the operator's point of view, the table may beconfigured to move the wafer carrier into a buffering space of the loadport, from front to back e.g. as in step 912, from left to right or fromright to left e.g. as in step 913, according to various embodiments.

It can be understood that the order of the steps shown in each of FIG. 8, FIG. 9A, and FIG. 9B may be changed according to different embodimentsof the present disclosure.

FIG. 10 illustrates a side view of an exemplary sky port 1010 with dooropening, closing and storage mechanisms, in accordance with someembodiments of the present disclosure. As shown in FIG. 10 , the skyport 1010 includes a housing 1011, a table 1012, a door opening/closingmechanism 1016, and a door storage space 1018. The sky port 1010 may belocated on a ceiling of a FAB to save floor area of the FAB.

The table 1012 may be configured to receive a wafer carrier 1020 from atransport tool, e.g. a vehicle of an OHT that is physically coupled tothe ceiling of the FAB and is located higher than the table 1012. Thewafer carrier 1020 has a door 1022 on the back of the wafer carrier1020, i.e. on the side facing the housing 1011.

The door opening/closing mechanism 1016 in this example is locatedinside the housing 1011 and located at the front side of the housing1011, i.e. at the side facing the wafer carrier 1020. The dooropening/closing mechanism 1016 may be configured to open the door 1022of the wafer carrier 1020, e.g. by a latch key and a vacuum pin, andmove the door 1022 away from the wafer carrier 1020 toward the back ofthe wafer carrier 1020 along the −X direction as shown in FIG. 10 . Thedoor opening/closing mechanism 1016 may then hold the door 1022 and moveit down along the −Z direction to the door storage 1018.

The door storage 1018 in this example is coupled to the housing 1011 andlocated at the front side of the housing 1011, i.e. at the side facingthe wafer carrier 1020 and below the table 1012. It can be understoodthat the door storage 1018 may be located at other places of the skyport 1010, e.g. on the other side of the housing 1011 and/or above thetable 1012. The door storage 1018 may be physically connected to thedoor opening/closing mechanism 1016. The door opening/closing mechanism1016 is movable relative to the door storage space 1018, along the Z and−Z directions. The door storage 1018 in this example includes four doorstorage units. It can be understood that a door storage space mayinclude one or more door storage units for storing wafer carrier doors.For example, after moving the door 1022 down to one of the door storageunits, the door opening/closing mechanism 1016 may rotate door pin bythe latch key to fix the door 1022 into the door storage unit. The door1022 is stored in the door storage unit while the wafer carrier 1020 isloaded by a load port for wafer processing.

In some embodiments, the sky port 1010 may also include a light shutter(not shown in FIG. 10 ). The light shutter may be coupled to the housing1011 and located at the front side of the housing 1011 and above thetable 1012, such that the wafer carrier 1020 is transported by atransport tool, e.g. an OHT, from up of the sky port 1010 along the −Zdirection, through the light shutter and down to the table 1012. Thelight shutter can capture light information of a wafer transport pathbetween the light shutter and the table 1012. Because any wafer carrieris received by the table 1012 through the wafer transport path, if thereis any object or obstacle located on the wafer transport path,continuing transporting wafer carriers may cause a collision. As such, asensor (not shown), e.g. an E84 sensor, that is electrically connectedto the light shutter may determine whether there is an obstacle on thewafer transport path based on the light information captured by thelight shutter and send a signal to the OHT, to stop OHT fromtransporting any more wafer carrier onto the table 1012, until the wafertransport path is clear and has no obstacle. For example, after an E84sensor connected to the light shutter determines that there is anobstacle between the light shutter and the table 1012, the E84 sensormay inform another sensor, e.g. an E87 sensor, connected to the OHT,about the obstacle to stop OHT from transporting wafer carriers to thetable 1012. Then, after the light information reflects that obstacle isgone and the wafer transport path is clear, the E84 sensor may informthe E87 sensor with another signal, to ask the OHT to continuetransporting wafer carriers to the table 1012.

In one embodiment, the sky port 1010 also includes a controller 1013.The controller 1013 may control the door opening/closing mechanism 1016to move, via a moving mechanism 1015, the door 1022 along the −Zdirection to an empty door storage unit in the door storage space 1018.In accordance with various embodiments, the controller 1013 may bedisposed under the table 1012 as shown in FIG. 10 , or disposed withinthe housing 1011, or disposed at other places of the sky port 1010. Thecontroller 1013 may be electrically or mechanically connected to thedoor opening/closing mechanism 1016 and the door storage space 1018.

After the door 1022 is opened and stored at the sky port 1010, the wafercarrier 1020 may be transported, e.g. by the OHT, to a load port. Theload port may load the wafer carrier 1020 for a processing tool toprocess at least one wafer in the wafer carrier 1020. The processingtool may be a manufacturing apparatus, a visual inspection apparatus, anelectrical characteristic test apparatus, etc.

After the wafer processing, the load port may unload the wafer carrier1020; and the wafer carrier 1020 may be transported back to the sky port1010. Then, the door opening/closing mechanism 1016 may be configured toretrieve a door from the door storage space 1018. The retrieved door maybe the original door 1022 of the wafer carrier 1020 before the wafercarrier 1020 is loaded, or may be another door having a same model asthe original door 1022 to fit the wafer carrier 1020. The dooropening/closing mechanism 1016 may hold and move, via the movingmechanism 1015, up the retrieved door along the Z direction from thecorresponding storage unit and close the retrieved door onto the wafercarrier 1020, e.g. by a latch key and a vacuum pin. In one embodiment,the moving mechanism 1015 may be part of the door opening/closingmechanism 1016 or separate but connected to the door opening/closingmechanism 1016. The OHT may transport the wafer carrier 1020 having thedoor 1022 closed back on it to another load port for further processingof the one or more wafers in the wafer carrier 1020.

In one embodiment, the sky port 1010 can serve several load ports at thesame time. In this case, after the sky port 1010 opens the door 1022,the wafer carrier 1020 is transported among the several load ports forwafer processing before being transported back to the sky port 1010 fordoor closing.

In another embodiment, one sky port serves one load port for one type ofwafer processing. In this case, after the sky port 1010 opens the door1022 and the wafer carrier 1020 is loaded and unloaded at thecorresponding load port, the wafer carrier 1020 is transported back tothe sky port 1010 for door closing. To perform another wafer processingon the wafers in the wafer carrier 1020, the wafer carrier 1020 will betransported to a second sky port for door opening, before beingtransported to a corresponding second load port for loading andprocessing.

In addition to serve a simple load port supporting one cassette or onewafer carrier at a time, the present teaching is also applicable to amulti-cassette load port (MCLP). When the sky port 1010 serves an MCLP,the controller 1013 may determine which door corresponds to which wafercarrier loaded on the MCLP. As such, when the sky port 1010 receivesback the wafer carrier 1020 from the MCLP, the controller 1013 candetermine where the corresponding door 1022 or where a matching doorhaving a same model as the door 1022 is stored. The controller 1013 maythen control the door opening/closing mechanism 1016 to move, via themoving mechanism 1015, the door 1022 or the matching door up along the Zdirection from the door storage unit in the door storage space 1018 fordoor closing.

The door opening/closing mechanism 1016 in the sky port 1010 may be thesame as the door opening/closing mechanism 116 shown in FIG. 2A and FIG.2B, in accordance with some embodiments of the present disclosure. Thedoor storage space 1018 in the sky port 1010 may be the same as the doorstorage space 118 as shown in FIG. 3A and FIG. 3B, in accordance withsome embodiments of the present disclosure.

FIG. 11 illustrates an exemplary sky port 1010 held on a ceiling 1130 ofa semiconductor FAB, in accordance with some embodiments of the presentdisclosure. As shown in FIG. 11 , the sky port 1010 is held onto theceiling 1130 of a FAB, by one or more connecting poles 1140. The poles1140 can physically connect the sky port 1010 to the ceiling 1130. Insome embodiments, the poles 1140 can be treated as part of the sky port1010. It can be understood that other holding mechanisms than the poles1140 can be used to hold the sky port 1010 onto the ceiling 1130.

As discussed above, while the sky port 1010 is held on the ceiling 1130,it can automatically open, close, and store wafer carrier doors 1122.Because a wafer carrier 1120 is transported to and from the sky port1010 by an OHT, that is also held on the ceiling 1130, the floor area ofthe FAB can be saved. In addition, the moving distance, in terms ofvertical distance, between the OHT and the sky port 1010 is small asthey are both coupled to the ceiling 1130. This can improve productionquality and operation safety. In one embodiment, the sky port 1010 canbe installed above or right above a corresponding load port, such thatspare space in the FAB can be utilized while wafer carriertransportation distance is minimized between devices in the FAB.

FIG. 12A illustrates a portion of an exemplary Automated MaterialHandling System (AMHS), in accordance with some embodiments of thepresent disclosure. FIG. 12B illustrates another portion of theexemplary AMHS shown in FIG. 12A, in accordance with some embodiments ofthe present disclosure. As shown in FIG. 12A and FIG. 12B, the OHT 1250may be used to transport a wafer carrier 1220 on the ceiling 1230 of aFAB. To load the wafer carrier 1220 for wafer processing, the OHT firsttransports the wafer carrier 1220 to a sky port 1210, that is physicallycoupled to the ceiling 1230 by one or more holding mechanisms 1240, fordoor opening and storing. The sky port 1210 may automatically open andstore a door of the wafer carrier 1220, as discussed above. Then theopened wafer carrier 1220′, whose door has been opened and stored at thesky port 1210, is picked up by the OHT 1250 and transported to a loadport 1260, e.g. an MCLP. The load port 1260 in this example includes atable 1262 for receiving the opened wafer carrier 1220′, and a pluralityof buffering spaces 1264 for loading and unloading multiple wafercarriers at the same time.

FIG. 13 illustrates a perspective view of an exemplary load port 1301for a processing tool 1302, in accordance with some embodiments of thepresent disclosure. As shown in FIG. 13 , the load port 1301 includes ahousing 1310, a carrier 1312, an input table 1314, and a plurality ofkey switches 1316. The carrier 1312 has a plurality of buffering spaces1320. The carrier 1312 is movable relative to the processing tool 1302that is coupled to the load port 1301. The input table 1314 isconfigured to receive at least one wafer carrier 1303, e.g. from an OHT,whose door has been opened and stored as discussed above.

In one embodiment, the carrier 1312 includes a plurality of supportingplates 1321, and the buffering spaces 1320 are respectively defined overthe supporting plates 1321. The carrier 1312 is movable relative to theprocessing tool 1302 along a first direction A1. The supporting plates1321 are arranged along the first direction A1. Any two adjacentsupporting plates 1321 are separated by a distance D along the firstdirection A1. The input table 1314 is movable relative to the supportingplates 1321 along a second direction A2 different from the firstdirection A1. A height H of the wafer carrier 1303 is smaller than thedistance D, so as to be received in the space between any two adjacentsupporting plates 121.

As shown in FIG. 13 , the housing 1310 has a doorway 1313 to the carrier1312. The load port 1301 further includes a door 1311 pivotallyconnected to the housing 1310 and capable of selectively opening andclosing the doorway 1313. When the load port 1301 malfunctions, thewafer carrier 1303 received in the carrier can be taken out via thedoorway 1313 by opening the door 1311.

The housing 1310 has an input gateway 1315 facing the input table 1314.The carrier 1312 is movably disposed in the housing 1310, and the inputtable 1314 is movable into and out of the aligned buffering space 1320via the input gateway 1315.

In one embodiment, the load port 1301 also includes a controller. Forwafer carrier loading, the controller may first control the plurality ofbuffering spaces to move up or down along the A1 direction, such thatone of the buffering spaces is aligned with the table 1314. Thecontroller may then control the table 1314 to move the wafer carrier1303 through the input gateway 1315 and into an aligned buffering spacealong the A2 direction, i.e. to load the wafer carrier 1303 into thealigned buffering space for the processing tool 1302 to process at leastone wafer in the wafer carrier 1303. The processing tool 1302 may becoupled to the load port 1301 for retrieving and processing wafers inthe wafer carriers (whose doors have been opened and stored in the doorstorage space 1018) that are buffered in the plurality of bufferingspaces in the housing 1310. The processing tool may be a manufacturingapparatus, a visual inspection apparatus, an electrical characteristictest apparatus, etc.

For wafer carrier unloading of the MCLP 1301, after the processing tool1301 finishes processing the at least one wafer in the wafer carrier1303, the controller may control the table 1314 to unload the wafercarrier 1303 from the aligned buffering space. It can be understood thatsince there are multiple wafer carriers buffered in the buffering spacesof the MCLP waiting for wafer processing, the previously alignedbuffering space may be misaligned with the table 1314. In this case, thecontroller may first control the buffering spaces to move up or downalong the A1 direction to realign the previously aligned buffering spacewith the table 1314, before controlling the table 1314 to unload thewafer carrier 1303 from the realigned buffering space.

As shown in FIG. 13 , the load port 1301 further includes a plurality ofkey-switches 1316. Different components of the load port 1301 may beconfigured to operate based on a pressed signal generated by any of thekey-switches 1316.

FIG. 14 illustrates a portion of a semiconductor FAB 1400 including atransport tool 1440, a sky port 1010 and a load port 1301, in accordancewith some embodiments of the present disclosure. The portion of the FAB1400 shown in FIG. 14 may be a schematic perspective diagram of anautomatic material handling system (AMHS). As shown in FIG. 14 , theAMHS includes a wafer transport tool 1440, e.g. an OHT system, a skyport 1010 that may be a sky port as disclosed above in accordance withFIGS. 10-12 , and a load port 1301 that may a load port as disclosedabove in accordance with FIG. 13 , e.g. an MCLP.

In one example, the OHT system 1440 includes a network of stationarytracks or rails 1442 operable to guide the movement of one or morewheeled OHT vehicles 1450 supported and suspended from the rails 1442.In some embodiments, the rails 1442 are monorails that are mounted toand suspended from the ceiling 1480 and/or walls of the FAB. Rails 1442have any suitable cross-sectional configuration as will be appreciatedby those in the art so long as the OHT vehicle 1450 are appropriatelysupported from the rail 1442 for rolling motion.

An OHT vehicle 1450 is operable to transport a wafer carrier 1420, 1420′through the FAB 1400 for intra-bay or inter-bay movement. The OHTvehicle 1450 is configured and structured to hold a wafer carrier 1420,1420′ housing a plurality of wafers and transport the wafer carrier1420, 1420′ in a generally horizontal or lateral direction from onelocation to another within the FAB 1400.

The OHT vehicle 1450 is configured and operable to pick up, raise/lower,hold, articulate, and release a wafer carrier 1420, 1420′. In oneembodiment, the OHT vehicle 1450 includes a motor-driven or pneumatichoisting mechanism 1452 generally comprised of gripper assemblyincluding one or more retractable and extendable gripper arms having agripper on the end thereof configured for locking onto a mating hook orflange on the wafer carrier 1420, 1420′. The hoisting mechanism 1452 isoperable to vertically raise and lower the gripper and attached wafercarrier 1420, 1420′.

As shown in FIG. 14 , the OHT vehicle 1450 can hold the wafer carrier1420 having a door 1422, transport the wafer carrier 1420 along the rail1442, and release the wafer carrier 1420 onto the table of the sky port1010. The sky port 1010 can automatically open and store the door 1422of the wafer carrier 1420, in a manner similar to what have beendescribed in FIGS. 10-12 . The sky port 1010 is physically coupled tothe ceiling 1480 by one or more holding mechanisms 1140, to save floorarea of the FAB 1400.

After the door 1422 is stored at the sky port 1010, the OHT vehicle 1450may pick up the opened wafer carrier 1420′ and transport the openedwafer carrier 1420′ to the load port 1301 that can load the opened wafercarrier 1420′ for a processing tool 1302 to process at least one waferin the opened wafer carrier 1420′. In this example, the processing tool1302 is coupled to the load port 1301. Both the load port 1301 and theprocessing tool 1302 are located on the floor 1490 of the FAB 1400.

In some embodiments, there are multiple processing tools in the FAB1400, and each processing tool is coupled to a corresponding load portthat is a load port as disclosed above in accordance with FIG. 13 . Inthis situation, after the at least one wafer in the wafer carrier 1420is processed and the door 1422 of the wafer carrier 1420 is closed backby the sky port 1010, the OHT vehicle 1450 can pick up the wafer carrier1420 from the sky port 1010 and transport the wafer carrier 1420 to anext sky port and a corresponding next load port for additional waferprocessing at the processing tool coupled to the next load port.

FIG. 15 is a flow chart illustrating an exemplary method 1500 forhandling wafer carriers, in accordance with some embodiments of thepresent disclosure. As shown in FIG. 15 , a wafer carrier having a doorand operable to hold a plurality of wafers, is received at 1504. Thedoor of the wafer carrier is opened at 1506. The door is stored at 1508in a door storage space of a device that is physically coupled to aceiling of a FAB.

FIG. 16 is a flow chart illustrating another exemplary method 1600 forhandling wafer carriers, in accordance with some embodiments of thepresent disclosure. As shown in FIG. 16 , a wafer carrier having a firstdoor and operable to hold a plurality of wafers, is received at 1604.The first door of the wafer carrier is opened with a latch key at 1606.The first door is moved away at 1608 from the wafer carrier along afirst direction. The first door is moved at 1610 along a directiondifferent from the first direction to a storage unit. As discussedabove, the storage unit may be included in a device that is physicallycoupled to a ceiling of a FAB.

The first door is attached at 1612 onto the storage unit in the devicefor storing the first door. At 1614, the wafer carrier is sent to a loadport for wafer processing. The wafer carrier that has been unloaded bythe load port is received at 1616. A second door having a same model asthe first door is retrieved at 1618. The second door is closed at 1620onto the wafer carrier.

It can be understood that the order of the steps shown in each of FIG.15 and FIG. 16 may be changed according to different embodiments of thepresent disclosure.

In an embodiment, an apparatus for handling wafer carriers in asemiconductor fabrication facility (FAB) is disclosed. The apparatusincludes: a table configured to receive a wafer carrier having a firstdoor and operable to hold a plurality of wafers; an opening mechanismconfigured to open the first door of the wafer carrier; and a doorstorage space configured to store the first door.

In another embodiment, a method for handling wafer carriers by a devicelocated on a floor of a FAB is disclosed. The method includes: receivinga wafer carrier having a first door and operable to hold a plurality ofwafers; opening the first door of the wafer carrier; storing the firstdoor in a door storage space of the device; and loading the wafercarrier whose door has been stored in the door storage space, into aprocessing tool to process at least one wafer in the wafer carrier.

In yet another embodiment, a method for handling wafer carriers by adevice in a FAB is disclosed. The method includes: receiving a wafercarrier having a first door and operable to hold a plurality of wafers;opening the first door of the wafer carrier; and storing the first doorin a door storage space of the device. The device is physically coupledto a ceiling of the FAB.

In still another embodiment, a wafer handling system in a FAB isdisclosed. The wafer handling system includes: a device that is coupledto a ceiling of the FAB, a load port, and a transport tool. The deviceis physically coupled to a ceiling of the FAB, and includes: a tableconfigured to receive a wafer carrier having a first door and operableto hold a plurality of wafers, an opening mechanism configured to openthe first door of the wafer carrier, and a door storage space configuredto store the first door. The load port is configured to receive thewafer carrier whose door has been stored in the storage space, and loadthe wafer carrier for a processing tool to perform a semiconductormanufacturing process on at least one wafer in the wafer carrier. Thetransport tool is configured to transport the wafer carrier between thedevice and the load port.

In a different embodiment, a wafer handling system in a FAB isdisclosed. The wafer handling system includes: a load port that islocated on a floor of the FAB, a transport tool physically coupled to aceiling of the FAB, and a processing tool physically coupled to the loadport. The load port includes: a table configured to receive a wafercarrier having a first door and operable to hold a plurality of wafers,an opening mechanism configured to open the first door of the wafercarrier, a door storage space configured to store the first door, and acontroller configured to control the table to load the wafer carrierwhose door has been stored in the door storage space. The transport toolis configured to transport the wafer carrier to the load port. Theprocessing tool is configured to process at least one wafer in theloaded wafer carrier.

The foregoing outlines features of several embodiments so that thoseordinary skilled in the art may better understand the aspects of thepresent disclosure. Those skilled in the art should appreciate that theymay readily use the present disclosure as a basis for designing ormodifying other processes and structures for carrying out the samepurposes and/or achieving the same advantages of the embodimentsintroduced herein. Those skilled in the art should also realize thatsuch equivalent constructions do not depart from the spirit and scope ofthe present disclosure, and that they may make various changes,substitutions, and alterations herein without departing from the spiritand scope of the present disclosure.

What is claimed is:
 1. An apparatus for handling wafer carriers in asemiconductor fabrication facility (FAB), comprising: a table configuredto receive a wafer carrier having a first door and operable to hold aplurality of wafers; an opening mechanism configured to open the firstdoor of the wafer carrier; a door storage space configured to store thefirst door; a housing comprising an input gateway configured for thewafer carrier to pass through; a controller configured to control thetable to move the wafer carrier through the input gateway and into abuffering space, wherein the buffering space is configured for aprocessing tool to process at least one wafer contained in the wafercarrier; and a light shutter located over the table and configured tocapture light information of a wafer transport path between the lightshutter and the table.
 2. The apparatus of claim 1, wherein: the wafercarrier is lowered by the transport tool onto a top surface of thetable; and wherein the controller is further configured to control thetable to load the wafer carrier whose door has been stored in the doorstorage space, into a processing tool to process at least one wafer inthe wafer carrier.
 3. The apparatus of claim 1, wherein: the controlleris further configured to control the table to unload the wafer carrierafter the at least one wafer is processed; and the apparatus furthercomprises a closing mechanism configured to retrieve a second doorhaving a same model as the first door from the door storage space, andclose the second door onto the wafer carrier that has been unloaded. 4.The apparatus of claim 1, further comprising: a first sensor configuredto determine whether there is an obstacle on the wafer transport pathbased on the light information, wherein the first sensor is furtherconfigured to inform a second sensor on the transport tool when there isan obstacle on the wafer transport path, to stop the transport tool fromtransporting wafer carriers to the apparatus.
 5. The apparatus of claim1, wherein the opening mechanism comprises: a vacuum pin configured tohold the first door; a latch key configured to open the first door; anda moving mechanism configured to move the first door away from the wafercarrier along a first direction, wherein: the door storage spaceincludes at least one storage unit for door storage; and the movingmechanism is further configured to: move the first door, along a seconddirection that is different from the first direction, to the at leastone storage unit that is not attached with any door, and attach thefirst door to the at least one storage unit by an alignment pin.
 6. Theapparatus of claim 5, further comprising: a plurality of bufferingspaces configured to buffer wafer carriers, whose doors have been openedand stored in the door storage space, before any wafer in the bufferedwafer carriers is processed by the processing tool; and a controllerconfigured to control the table to move the wafer carrier into one ofthe plurality of buffering spaces along at least one of: the firstdirection and a third direction that is different from the firstdirection.
 7. The apparatus of claim 1, further comprising one or moreholding mechanisms configured to hold the apparatus to the ceiling ofthe FAB.
 8. The apparatus of claim 1, wherein the apparatus isassociated with a processing tool configured to perform a semiconductormanufacturing process on at least one wafer in the wafer carrier.
 9. Theapparatus of claim 1, the table is configured to receive the wafercarrier from vehicle that is physically coupled to a ceiling of a roomin which the apparatus is located.
 10. The apparatus of claim 1, furthercomprising a sensor to detect an object located on a transport path ofthe wafer carrier.
 11. A method for handling wafer carriers by a devicelocated on a floor of a FAB, comprising: receiving a wafer carrierhaving a first door and operable to hold a plurality of wafers, whereinthe wafer carrier is transported by a transport tool; opening the firstdoor of the wafer carrier along a first direction; storing the firstdoor in a door storage space of the device; loading the wafer carrierwhose door has been stored in the door storage space, into a processingtool to process at least one wafer in the wafer carrier; capturing lightinformation of a wafer transport path through which the wafer carrier isreceived; determining whether there is an obstacle on the wafertransport path based on the light information; and informing thetransport tool when there is an obstacle on the wafer transport path, tostop the transport tool from transporting wafer carriers to the device.12. The method of claim 11, further comprising: unloading the wafercarrier that has been loaded; retrieving a second door having a samemodel as the first door from the door storage space, and closing thesecond door onto the wafer carrier that has been unloaded.
 13. Themethod of claim 11, further comprising: moving the wafer carrier, alongat least one of: the first direction and a second direction that isdifferent from the first direction, into a buffering space in thedevice; and buffering the wafer carrier, whose door has been opened andstored in the door storage space, in the buffering space before anywafer in the wafer carrier is processed.
 14. The method of claim 13,wherein: a controller controls a table upon which the wafer carrierrests to move the wafer carrier into the buffering space.
 15. The methodof claim 11, wherein: opening the first door further comprises: holdingthe first door, opening the first door when the first door is beingheld, and moving the first door away from the wafer carrier along thefirst direction; the door storage space includes at least one storageunit for door storage.
 16. The method of claim 15, further comprising:moving the first door, along a third direction that is different fromthe first direction, to the at least one storage unit that is notattached with any door; and attaching the first door onto the at leastone storage unit.
 17. A method for handling wafer carriers by a devicein a FAB, comprising: receiving a wafer carrier having a first door andoperable to hold a plurality of wafers; opening the first door of thewafer carrier; and moving the wafer carrier through an input gateway ofthe device into a buffering space of the device, wherein the bufferingspace is configured for a processing tool to process at least one wafercontained in the wafer carrier.
 18. The method of claim 17, wherein thewafer carrier is configured to be loaded by a load port for theprocessing tool to perform a semiconductor manufacturing process on theat least one wafer in the wafer carrier.
 19. The method of claim 18,further comprising: storing the first door in a door storage space ofthe device; receiving the wafer carrier that has been unloaded by theload port after wafer processing; retrieving a second door having a samemodel as the first door from the door storage space; and closing thesecond door onto the wafer carrier that has been unloaded by the loadport.
 20. The method of claim 19, wherein: opening the first door of thewafer carrier comprises: holding the first door, opening the first doorwhen the first door is being held, and moving the first door away fromthe wafer carrier along a first direction; the door storage spaceincludes at least one storage unit for door storage; and the methodfurther comprises: moving the first door, along a second direction thatis different from the first direction, to the at least one storage unitthat is not attached with any door, and attaching the first door to theat least one storage unit by an alignment pin.